When a bundle of relatively slender cables, a relatively small-sized FPC or the like is electrically connected with a main circuit board, such as a solid printed circuit board, on which various electrical parts are directly mounted, there has been often proposed to use a first electrical connector on the side of cables or the like with which the cables or the FPC is connected and a second electrical connector on the side of a circuit board which is mounted on a main circuit board to be electrically connected with the same and with which the first electrical connector is engaged. The first electrical connector is operative to be a mating electrical connector to the second electrical connector and the second electrical connector is operative to be a mating electrical connector to the first electrical connector.
In such a case, the first electrical connector constitutes a plug type electrical connector comprising, for example, an insulated housing on which an engaging portion forming a connectively engaging protrusion on which a plurality of conductive contacts are arranged to be electrically connected respectively with the cables is provided. Usually, the first electrical connector constituting the plug type electrical connector comprises also a conductive shell or cover formed by means of processing a metal thin plate and mounted on the insulated housing for covering partially the same to be grounded for shielding the conductive contacts arranged on the engaging portion of the insulated housing from electromagnetic wave noise coming from the outside. The second electrical connector operative to be the mating electrical connector to the first electrical connector constitutes a receptacle type electrical connector comprising, for example, an insulated housing on which an engaging portion forming a connectively engaging opening into which the connectively engaging protrusion provided on the insulated housing of the first electrical connector is inserted is provided. In the connectively engaging opening provided on the insulated housing of the second electrical connector, portions of a plurality of conductive contacts, an end of each of which constitutes a terminal connected electrically with the main circuit board, are arranged. Usually, the second electrical connector constituting the receptacle type electrical connector comprises also a conductive shell or cover formed by means of processing a metal thin plate and mounted on the insulated housing for covering partially the same to be grounded for shielding the conductive contacts arranged in the insulated housing from electromagnetic wave noise coming from the outside. Under such a situation, when the connectively engaging protrusion provided on the insulating housing of the first electrical connector is inserted into the connectively engaging opening provided on the insulated housing of the second electrical connector to engage with the same, the conductive contacts of the first electrical connector come into contact respectively with the conductive contacts of the second electrical connector to be connected electrically with the same.
With the above-described first electrical connector constituting the plug type electrical connector with which the bundle of cables or the FPC is connected and the second electrical connector constituting the receptacle type electrical connector mounted on the main circuit board, when the engaging portion provided on the insulated housing of the first electrical connector to form the connectively engaging protrusion is engaged with the engaging portion provided on the insulating housing of the second electrical connector to form the connectively engaging opening, it is required that the first electrical connector is appropriately maintained in engagement with the second electrical connector. Accordingly, there have been proposed previously several measures or means for putting a couple of electrical connectors having engaging portions provided on respective insulating housings to be engaged with each other, such as the first and second electrical connectors mentioned above, in a condition wherein the engaging portions are appropriately maintained in engagement with each other.
In one of such previously proposed measures or means, one of the first and second electrical connectors, which has the engaging portion provided on the insulated housing to form the connectively engaging protrusion or opening, is provided with a manipulative lever or manipulative rod set to be rotatable in respect to the insulated housing thereof. When the engaging portion of the first electrical connector forming the connectively engaging protrusion is put in engagement with the engaging portion of the second electrical connector forming the connectively engaging opening, the manipulative lever or manipulative rod of one of the first and second electrical connectors is manipulated to rotate for engaging with the insulated housing of the other of the first and second electrical connectors so that the engaging portion of the first electrical connector is prevented from getting out of the engaging portion of the second electrical connector. (As disclosed in, for example, patent document 1).
In such a pair of first and second electrical connectors to which the previously proposed measure or means is applied, as shown in the patent document 1 published previously, wherein the connectively engaging protrusion provided on the insulated housing of the first electrical connector (the plug type electrical connector) is put in engagement with the connectively engaging opening provided on the insulated housing of the second electrical connector (the receptacle type electrical connector), the first electrical connector is provided with a rotatable manipulative lever (a locking lever) which is mounted on the insulated housing having an outside surface thereof covered partially by the conductive shell and the second electrical connector is provided with a holding portion which is formed in the conductive shell covering partially an outside surface of the insulated housing and operative to engage with the rotatable manipulative lever of the first electrical connector for holding the same. The rotatable manipulative lever mounted on the insulated housing of the first electrical connector is made of material shaped into a bar to have a main manipulatable portion including a central portion of the rotatable manipulative lever and a pair of end portions provided at both ends of the main manipulatable portion. Each of the end portions of the rotatable manipulative lever is folded back from the end of the main manipulatable portion so that a top end of one of the end portions is opposite to a top end of the other of the end portions. The end portions thus formed constitute a pair of rotary axes which are loosely inserted respectively in both end portions in a longitudinal direction of the insulated housing to be rotatably held by the insulated housing. The holding portion formed in the conductive shell of the second electrical connector is shaped into a cantilever spring projecting from a part of the conductive shell (a board connecting portion).
When the connectively engaging protrusion provided on the insulated housing of the first electrical connector is engaged with the connectively engaging opening provided on the insulated housing of the second electrical connector, the rotatable manipulative lever mounted on the insulated housing of the first electrical connector is manipulated to rotate so that the main manipulatable portion of the rotatable manipulative lever is caused to come close to a portion of the insulated housing of the second electrical connector, which is opposite to the connectively engaging opening provided thereon, and then to ride across the holding portion formed in the conductive shell of the second electrical connector so as to engage with the same. Thereby, the main manipulatable portion of the rotatable manipulative lever is held by the holding portion so that a condition wherein the first and second electrical connectors are engaged with each other is stably maintained and the connectively engaging protrusion provided on the insulated housing of the first electrical connector is prevented from getting out of the connectively engaging opening provided on the insulated housing of the second electrical connector.    Patent Document 1: Japanese Patent Publication No. 2008-112700 (Pages 4 to 6, FIGS. 1 to 5)